1. Field of the Invention
The present invention relates to a rotary connector attached to a steering device of an automobile or the like and used as electrical connection means between electrical devices such as a steering heater device, and an air bag system and the like provided to a vehicle body.
2. Description of the Related Art
Hereinafter, drawings of a conventional rotary connector are explained. FIG. 15 is a plan view showing a conventional rotary connector, FIG. 16 is a main part sectional view taken along line 16xe2x80x9416 in FIG. 15, FIG. 17 relates to the conventional rotary connector and is a perspective view showing a connection state of a lead block and a flexible cable, and FIG. 18 relates to the conventional rotary connector and is an exploded perspective view showing the connection state of the lead block and the flexible cable.
This rotary connector 80 is installed on a steering device (not shown) of an automobile or the like and is used as electrical connection means of a steering heater circuit mounted to a steering wheel, an air bag circuit, a horn circuit, and other switch circuits, and is basically constituted by a pair of a stationary housing 61 and a movable housing 62 concentrically arranged and relatively rotatably coupled with each other, a flexible cable 71 (see FIG. 17) accommodated in a space as an annular cable accommodating portion (not shown) formed between the pair of the stationary and movable housings 61 and 62 to be capable of being wound up and rewound, and a first and a second lead blocks 63 and 64 respectively connected to both end portions of the flexible cable 71.
As shown in FIGS. 17 and 18, the flexible cable 71 includes two insulating films 71a as band-like base films, and plural (for example, ten) conductor portions 71b stuck between the two insulating films 71a and made of very thin band-like copper foils or the like, and the respective conductor portions 71b are stuck in a parallel state.
In the rotary connector 80 basically structured like this, the stationary housing 61 is fixed to a vehicle body (not shown), and the movable housing 62 is fixed to a handle member (not shown), and both ends of the flexible cable 71 are connected to respective electrical devices at the vehicle body and handle side through the respective first and second lead blocks 63 and 64 at the stator side and the movable side, so that it is used as electrical connection means of a steering heater circuit device, a vehicle-mounted air bag system, a horn circuit and the like.
The stationary housing 61 made of synthetic resin material is, as shown in FIG. 15, equipped with a cylindrical outer tube portion 65, a bottom wall 66 provided at an end portion of the outer tube portion 65, and one first receiving body 67 projecting outward from the vicinity of an outer peripheral end of the bottom wall 66.
On the other hand, the movable housing 62 made of synthetic resin material is equipped with a cylindrical inner tube portion 68, an upper wall 69 provided at an end portion of the inner tube portion 68, and one second receiving body 70 projecting outward from the vicinity of an outer peripheral end of the upper wall 69.
The second lead block 64 is, as shown in FIGS. 17 and 18, equipped with one base member 64a made of synthetic resin material, plural (for example, ten) terminals 64b formed at the base member 64a by insert molding and made of metal material, and a hole portion 64c through which part of the terminals 64b pass and in which the partial terminals 64b are exposed.
Besides, the terminals 64b are equipped with first terminal portions 64d projecting outward from the base member 64a, and second terminal portions 64e respectively integrated with the first terminal portions 64d, passing through the hole portion 64c, and exposed. The first terminal portions 64d are straightly extended outward from the root portion of the base member 64a and are aligned on the same straight lines, and the second terminal portions 64e are extended in the direction orthogonal to the first terminal portions 64d. 
Besides, the base member 64a includes a rectangular parallelepiped first base portion 64f in which the hole portion 64c is formed, a second base portion 64g extended from one end face of the first base portion 64f in an orthogonal direction, and a third base portion 64h extended from one end face of the second base portion 64g in an upper direction parallel to the first base portion 64f. That is, the whole of the base member 64a is formed into a stair shape with the first base portion 64f, the second base portion 64g, and the third base portion 64h. 
In this state, the first terminal portions 64d are extended outward from an upper surface wall of the third base portion 64h. 
Besides, the respective conductor portions 71b of the flexible cable 71 are connected to the second terminal portions 64e passing through the hole portion 64c formed in this first base portion 64f by suitable means such as, for example, ultrasonic bonding.
This second lead block 64 is held in the second receiving body 70 of the movable housing 62, and one end portion of the one flexible cable 71 is electrically and mechanically connected to the respective terminals 64b. 
The first lead block 63 is equipped with a base portion 63a made of synthetic resin material, plural (for example, ten) terminals 63b formed at the base portion 63a by insert molding and made of metal material, and a hole portion (not shown) through which part of the terminals 63b pass and in which the partial terminals 63b are exposed.
Besides, the terminals 63b are equipped with first terminal portions 63c projecting outward from the base portion 63a, and second terminal portions (not shown) respectively integrated with the first terminal portions 63c, passing through the hole portion (not shown), and exposed.
The first terminal portions 63c are straightly extended from the root portion of the base portion 63a and are aligned on the same straight line, and the second terminal portions (not shown) are extended in the direction orthogonal to the first terminal portions 63c. 
That is, this first lead block 63 is formed to have substantially the same structure as the structure of the second lead block 64.
This first lead block 63 is held in the first receiving body 67 of the stationary housing 61, and the other end portion of the one flexible cable 71 connected to the terminals 63b is electrically and mechanically connected to the respective terminals 63b. 
Besides, with respect to the respective terminals 63b and 64b of the first and the second lead blocks 63 and 64, two connectors, for example, a first external female connector (not shown) for a steering heater circuit, and a second external female connector (not shown) for an air bag circuit and a horn circuit are respectively inserted in the first and the second receiving bodies 67 and 70, and electrical connection is realized.
Next, here, an attachment structure of the second lead block 64 concerning the foregoing conventional rotary connector 80 to the movable housing 62 will be described by the use of FIG. 16.
At this time, the second lead block 64 is made of the one base member 64a, and the flexible cable 71 (see FIG. 17) is connected to the base member 64a. 
In this state, first, the first base portion 64f of the base member 64a of the second lead block 64 is inserted and disposed in a concave portion 68a disposed at a predetermined position of the cylindrical inner tube portion 68 of the movable housing 62.
Next, the upper wall 69 on which the second receiving body 70 is provided is disposed so that the third base portion 64h is attached in the second receiving body 70, and then, the inner tube portion 68 and the upper wall 69 are fixed by suitable means.
In the conventional rotary connector 80, according to the vehicle family of the automobile in which it is to be installed, the grade in the same vehicle family, and the like, the respective connector shapes of external female connectors which can be connected to the respective terminals 63b (first terminal portions 63c) and 64b (first terminal portions 64d) of the first and the second lead blocks 63 and 64, and the number of the respective terminals are varied. Thus, it is necessary to vary the shapes of and the numbers of the first terminal portions 63c and 64d of the first and the second lead blocks 63 and 64 so that they correspond to the respective connector shapes of the external female connectors and the number of the respective terminals.
Besides, the number of the conductor portions 71b of the flexible cable 71 is also varied according to a use, and the flexible cable 71 having a different number of the conductor portions 71b has been used.
However, recently, there has appeared a thing in which irrespective of the vehicle family of an automobile or the grade in the same vehicle family, the number of the respective conductor portions 71b of the flexible cable 71 is set to a maximum number (for example, ten) used for electrical connection between respective electrical devices, this flexible cable 71 is used in common, and only the lead blocks 63 and 64 are varied.
That is, the number of the second terminal portions 64e of the varied lead blocks 63 and 64 is set to the maximum number similarly to the number of the respective conductor portions 71b of the flexible cable 71, the respective conductor portions 71b are connected to the respective second terminal portions 64e, and the shapes of and the number of only the first terminal portions 64d are formed to correspond to the shapes of and the number of the external female connectors. In the conventional example, although the description has been given of the case where the number of the first terminal portions 64d is equal to the number of the second terminal portions 64e, there is a case where the number of the first terminal portions 64d is not larger than the number of the second terminal portions 64e. Thus, eventually, the variety of the lead blocks 63 and 64 is increased.
In other words, in the lead blocks 63 and 64 of the conventional rotary connector 80, for each of external female connectors which can be connected to the respective first terminal portions 64d, it becomes necessary to form all shapes of the lead blocks 63 and 64 to cope with each of them. From this, the variety of the lead blocks 63 and 64 is increased, and in the lead blocks 63 and 64, the structures of the one stair-shaped base member 64a, and the respective terminals 64b formed of the first terminal portions 64d and the second terminal portions 64e, which are subjected to the insert molding and are different in the number, are complicated, and the metal molds of the lead blocks 63 and 64 forming the. complicated structures become necessary, and accordingly, there is a problem that the cost of the rotary connector 80 becomes high.
The invention has an object to provide an inexpensive rotary connector by simplifying and standardizing a lead block.
A rotary connector of the invention comprises a stationary housing to which a first lead block is attached, a movable housing to which a second lead block is attached and which is rotatably mounted to the stationary housing, and a flexible cable which is accommodated in an accommodating portion formed between the stationary housing and the movable housing, and includes N conductor portions, each of the N conductor portions being connected to each of the first and the second lead blocks,
at least one of the first and the second lead blocks includes a first base member and a second base member, the first base member includes a first base portion, and N terminals integrated with the first base portion, the N terminals include N first terminal portions projecting outward from the first base portion, and N second terminal portions exposed from the first base portion, the second base member includes a second base portion and N or less terminals integrated with the second base portion, the N or less terminals include N or less first and second external terminal portions projecting outward from the second base portion, respective terminal portions of the N conductor portions of the flexible cable are connected to the N second terminal portions of the first base member, the N or less respective second external terminal portions of the second base member are connected to some of the N first terminal portions of the first base member, and the first external terminal portions can be connected to an external female connector terminal.
By such structure, since the flexible cable including the N conductor portions and the first base member including the N second terminal portions of the lead block can be made to have versatility and standardized, the variety of the flexible cable and the first base member can be reduced, and further, since it is possible to cope with an external female connector, which can be connected to the respective terminals of the second base member, by changing only the structure of the second base member including the N or less first and second external terminal portions, the flexible cable and the first base member have the versatility, and since the second base member is constituted by only the second base portion and the first and the second external terminal portions projecting outward from the second base portion, the second base member has the simple structure and is inexpensive, and from this, it is possible to provide the rotary connector equipped with the flexible cable having the versatility and the inexpensive lead block.
Besides, in the rotary connector of the invention, the N first terminal portions of the first base member are disposed in a direction orthogonal to a lead direction of the conductor portions of the flexible cable and on the same straight line, and tips of the second external terminal portions of the second base member are disposed on a same straight line.
By such structure, the first terminal portions of the first base member are easily connected to the second external terminal portions of the second base member, and it is possible to provide the rotary connector equipped with the inexpensive lead block.
Besides, in the rotary connector of the invention, the first terminal portions of the first base member are disposed at equal intervals.
By such structure, since the first terminal portions are disposed at equal intervals, the first base member is easily formed, and it is possible to provide the rotary connector equipped with the inexpensive lead block.
Besides, in the rotary connector of the invention, a hole portion is provided in the first base portion of the first base member, and the second terminal portions are exposed from the hole portion.
By such structure, since the second terminal portions are held in a state where they are exposed from the hole portion, the second terminal portions are certainly held to the first base portion, and accordingly, it is possible to provide the rotary connector equipped with the lead block in which the conductor portions of the flexible cable are stably connected to the second terminal portions.
Besides, in the rotary connector of the invention, the first external terminal portions of the second base member are constituted by at least two groups of a first terminal group and a second terminal group different in terminal shape.
By such structure, it is possible to provide the rotary connector equipped with the lead block in which respective external female connectors can be certainly connected to the first and the second terminal groups.
Besides, in the rotary connector of the invention, the first external terminal portions of the second base member are formed of lead wires.
By such structure, it is possible to provide the rotary connector equipped with the lead block which includes the first external portions having flexibility and easy to pull about because of the formation of the lead wires and has a high degree of freedom in attachment.
Besides, the rotary connector of the invention is structured to comprise a stationary housing to which a first lead block is attached,
a movable housing to which a second lead block is attached and which is rotatably mounted to the stationary housing, and
a flexible cable which is accommodated in an accommodating portion formed between the stationary housing and the movable housing, and includes N conductor portions, each of the N conductor portions being connected to each of the first and the second lead blocks, wherein
at least one of the first and the second lead blocks includes a first, a second and a third terminal blocks,
the first terminal block includes a first base portion made of insulating material, and N first terminals embedded in and attached to the first base portion,
the N first terminals include N terminal portions projecting outward from the first base portion, and N exposed portions electrically connected to the respective terminal portions and exposed from the first base portion, the N respective conductor portions of the flexible cable are connected to the respective exposed portions,
the second terminal block includes a second base portion made of insulating material, and N or less second terminals embedded in and attached to the second base portion and equipped with first and second external terminal portions projecting outward from the second base,
the third terminal block includes a third base made of insulating material, and N or less third terminals embedded in and attached to the third base and equipped with third and fourth external terminal portions projecting outward from the third base,
each of the second and the fourth external terminal portions of the second and the third terminal blocks is connected to any one of the N terminal portions of the first terminal block, and the first and the third external terminal portions can be connected to an external connector terminal.
By such structure, the lead block can be divided into the first, the second, and the third terminal blocks, and the respective structures can be simplified, and by this, a metal mold for molding becomes simple and inexpensive, and the inexpensive rotary connector can be provided.
Besides, the first terminal block can be standardized, the second and the third terminal blocks can also be standardized, and various combinations become applicable by the combination of the second and the third blocks, and an adaptable one can be obtained.
Besides, the rotary connector of the invention is structured such that the N terminal portions of the first terminal block are led out in a direction orthogonal to an extension direction of the conductor portions of the flexible cable, the N terminal portions are disposed on a straight line, and the second and the fourth terminal portions are connected to the N terminal portions on the straight line.
By such structure, the connection of the second and the third blocks to the terminal portions is easy, and it is possible to provide the rotary connector equipped with the inexpensive lead block.
Besides, the rotary connector of the invention is structured such that the N terminal portions of the first terminal block are disposed at equal intervals.
By such structure, since the terminal portions are disposed at equal intervals, the first terminal block can be easily formed, and further, the connection of the second and the third blocks to the terminal portions is easy, and it is possible to provide the rotary connector equipped with the inexpensive lead block.
Besides, the rotary connector of the invention is structured such that a hole portion is provided in the first base, and the exposed portions of the first terminals are exposed from the hole portion.
By such structure, it is possible to provide the rotary connector equipped with the lead block in which the connection of the conductor portions of the flexible cable to the exposed portions is easy, and the connection of both is certain.
Besides, the rotary connector of the invention is structured such that the second and the third bases of the second and the third terminal blocks are disposed side by side in a direction in which they overlap with each other.
By such structure, the second and the fourth external terminal portions of the second and the third terminal blocks can be disposed in a juxtaposition state, and it is possible to provide one which can simply and easily cope with external female connectors, and is small.
Besides, the rotary connector of the invention is structured such that the numbers of the second and the fourth external terminal portions of the second and the third terminal blocks are respectively N/2, and the second and the fourth external terminal portions are alternately connected to the N terminal portions of the first terminal block.
By such structure, the connection of the second and the third terminal blocks to the terminal portions becomes simple and easy, and it is possible to provide one having an excellent productivity.